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Gonna take some time to appreciate this ED. It opens up with characters' umbrellas popping up in episode order. It's nothing deep but I always love little easter eggs like that. Next is all the girls drawn with an art style I really love, same as from Fly Me to the Star (Revstar)
Then it shows them all alone looking at the sky melancholically, due to brightly colored raindrops. The transition to the next scene is Yuu jumping forward, black umbrella in hand. I hope this means she will join the club, but it could also just show how much she supports them.
As the chorus kicks in, the camera pans from the rainy sky to all the girls with their umbrellas over their heads, ready to go forward because they are together. Also I think the umbrellas symbolize their personal attributes and values, the ones that each episode focuses on.
I also love how expressive their poses are, they really capture their respective personalities. The final shot is amazing. The raindrops combined with their sparkle made a rainbow, which symbolizes the club as a whole. I think the school being called "Niji"gasaki is no accident.
